1. Field of the Invention
The invention relates to novel o-aminophenol derivatives and to agents containing said compounds for coloring keratin fibers.
2. Description of Related Art
In the field of coloring keratin fibers, in particular hair coloring, oxidation dyes have achieved significant importance. The coloration arises here as a result of the reaction of certain developer substances with certain coupler substances in the presence of a suitable oxidizing agent. The developer substances used here are, in particular, 2,5-diaminotoluene, 2,5-diaminophenylethyl alcohol, p-aminophenol, 1,4-diaminobenzene and 4,5-diamino-1-(2-hydroxyethyl)pyrazole, while examples of coupler substances are resorcinol, 2-methylresorcinol, 1-naphthol, 3-aminophenol, m-phenylenediamine, 2-amino-4-(2′-hydroxyethyl)aminoanisole, 1,3-diamino-4-(2′-hydroxyethoxy)benzene and 2,4-diamino-5-fluorotoluene.
Besides the stability of the colorations over at least 4 to 6 weeks, numerous additional requirements are placed on oxidation dyes that are used for coloring human hair. For example, the dyes must be acceptable from a toxicological and dermatological point of view, and the hair colorations achieved should have good light fastness, permanent wave fastness, rubbing fastness and stability to shampooing, and also adequate resistance to perspiration excretions. Furthermore, it is required that, by combining suitable developer substances and coupler substances, a broad palette of different color nuances can be produced.
A particular problem when nuancing relatively light color tones is the even absorption of dye from the hair roots to the hair ends, and also the durability of the nuances to a permanent wave treatment. The use of direct yellow-coloring aromatic nitro dyes together with oxidative hair color precursors can solve the described problem in part, but the stability of the colorations over a period of several weeks is often unsatisfactory.
To solve the described problem, DE-A 28 33 989 proposes the use of 6-amino-3-methylphenol as oxidative yellow coloring agent in oxidative hair colorants. This compound is said to have good suitability as nuancing dye for producing light blond tones and gold tones, although the set requirements are not completely satisfied particularly with regard to the stability of the hair colorations to the effect of permanent waving compositions.